Ignore service principal password resources from Terraform state management

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What is the current behavior?

Currently, all azure resource(s) state changes related to the service principal password are managed through Terraform. This results in state changes being triggered for Terraform incremental builds as the password is randomly generated on each run. The impact is Terraform attempts to delete and recreate the password and KV secrets on each incremental deployment, regardless of template changes. Terraform should only be responsible for creating resources like the SP password and keyvault secrets when bootstrapping the initial azure environment.

Issue Number: #330

What is the new behavior?

Terraform resource types such as service prinipal passwords and keyvault secrets capturing sp passwords are ignored from state change lifecycles events via

lifecycle {
    ignore_changes = ["value"]
  }

Does this introduce a breaking change?

[NO]

microsoft / cobalt